qobject/qdict.c

   1 /*
   2  * QDict Module
   3  *
   4  * Copyright (C) 2009 Red Hat Inc.
   5  *
   6  * Authors:
   7  *  Luiz Capitulino <lcapitulino@redhat.com>
   8  *
   9  * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
  10  * See the COPYING.LIB file in the top-level directory.
  11  */
  12
  13 #include "qemu/osdep.h"
  14 #include "qapi/qmp/qnum.h"
  15 #include "qapi/qmp/qdict.h"
  16 #include "qapi/qmp/qbool.h"
  17 #include "qapi/qmp/qnull.h"
  18 #include "qapi/qmp/qstring.h"
  19 #include "qobject-internal.h"
  20
  21 /**
  22  * qdict_new(): Create a new QDict
  23  *
  24  * Return strong reference.
  25  */
  26 QDict *qdict_new(void)
  27 {
  28     QDict *qdict;
  29
  30     qdict = g_malloc0(sizeof(*qdict));
  31     qobject_init(QOBJECT(qdict), QTYPE_QDICT);
  32
  33     return qdict;
  34 }
  35
  36 /**
  37  * tdb_hash(): based on the hash algorithm from gdbm, via tdb
  38  * (from module-init-tools)
  39  */
  40 static unsigned int tdb_hash(const char *name)
  41 {
  42     unsigned value;    /* Used to compute the hash value.  */
  43     unsigned   i;      /* Used to cycle through random values. */
  44
  45     /* Set the initial value from the key size. */
  46     for (value = 0x238F13AF * strlen(name), i = 0; name[i]; i++) {
  47         value = (value + (((const unsigned char *)name)[i] << (i * 5 % 24)));
  48     }
  49
  50     return (1103515243 * value + 12345);
  51 }
  52
  53 /**
  54  * alloc_entry(): allocate a new QDictEntry
  55  */
  56 static QDictEntry *alloc_entry(const char *key, QObject *value)
  57 {
  58     QDictEntry *entry;
  59
  60     entry = g_malloc0(sizeof(*entry));
  61     entry->key = g_strdup(key);
  62     entry->value = value;
  63
  64     return entry;
  65 }
  66
  67 /**
  68  * qdict_entry_value(): Return qdict entry value
  69  *
  70  * Return weak reference.
  71  */
  72 QObject *qdict_entry_value(const QDictEntry *entry)
  73 {
  74     return entry->value;
  75 }
  76
  77 /**
  78  * qdict_entry_key(): Return qdict entry key
  79  *
  80  * Return a *pointer* to the string, it has to be duplicated before being
  81  * stored.
  82  */
  83 const char *qdict_entry_key(const QDictEntry *entry)
  84 {
  85     return entry->key;
  86 }
  87
  88 /**
  89  * qdict_find(): List lookup function
  90  */
  91 static QDictEntry *qdict_find(const QDict *qdict,
  92                               const char *key, unsigned int bucket)
  93 {
  94     QDictEntry *entry;
  95
  96     QLIST_FOREACH(entry, &qdict->table[bucket], next)
  97         if (!strcmp(entry->key, key)) {
  98             return entry;
  99         }
 100
 101     return NULL;
 102 }
 103
 104 /**
 105  * qdict_put_obj(): Put a new QObject into the dictionary
 106  *
 107  * Insert the pair 'key:value' into 'qdict', if 'key' already exists
 108  * its 'value' will be replaced.
 109  *
 110  * This is done by freeing the reference to the stored QObject and
 111  * storing the new one in the same entry.
 112  *
 113  * NOTE: ownership of 'value' is transferred to the QDict
 114  */
 115 void qdict_put_obj(QDict *qdict, const char *key, QObject *value)
 116 {
 117     unsigned int bucket;
 118     QDictEntry *entry;
 119
 120     bucket = tdb_hash(key) % QDICT_BUCKET_MAX;
 121     entry = qdict_find(qdict, key, bucket);
 122     if (entry) {
 123         /* replace key's value */
 124         qobject_unref(entry->value);
 125         entry->value = value;
 126     } else {
 127         /* allocate a new entry */
 128         entry = alloc_entry(key, value);
 129         QLIST_INSERT_HEAD(&qdict->table[bucket], entry, next);
 130         qdict->size++;
 131     }
 132 }
 133
 134 void qdict_put_int(QDict *qdict, const char *key, int64_t value)
 135 {
 136     qdict_put(qdict, key, qnum_from_int(value));
 137 }
 138
 139 void qdict_put_bool(QDict *qdict, const char *key, bool value)
 140 {
 141     qdict_put(qdict, key, qbool_from_bool(value));
 142 }
 143
 144 void qdict_put_str(QDict *qdict, const char *key, const char *value)
 145 {
 146     qdict_put(qdict, key, qstring_from_str(value));
 147 }
 148
 149 void qdict_put_null(QDict *qdict, const char *key)
 150 {
 151     qdict_put(qdict, key, qnull());
 152 }
 153
 154 /**
 155  * qdict_get(): Lookup for a given 'key'
 156  *
 157  * Return a weak reference to the QObject associated with 'key' if
 158  * 'key' is present in the dictionary, NULL otherwise.
 159  */
 160 QObject *qdict_get(const QDict *qdict, const char *key)
 161 {
 162     QDictEntry *entry;
 163
 164     entry = qdict_find(qdict, key, tdb_hash(key) % QDICT_BUCKET_MAX);
 165     return (entry == NULL ? NULL : entry->value);
 166 }
 167
 168 /**
 169  * qdict_haskey(): Check if 'key' exists
 170  *
 171  * Return 1 if 'key' exists in the dict, 0 otherwise
 172  */
 173 int qdict_haskey(const QDict *qdict, const char *key)
 174 {
 175     unsigned int bucket = tdb_hash(key) % QDICT_BUCKET_MAX;
 176     return (qdict_find(qdict, key, bucket) == NULL ? 0 : 1);
 177 }
 178
 179 /**
 180  * qdict_size(): Return the size of the dictionary
 181  */
 182 size_t qdict_size(const QDict *qdict)
 183 {
 184     return qdict->size;
 185 }
 186
 187 /**
 188  * qdict_get_double(): Get an number mapped by 'key'
 189  *
 190  * This function assumes that 'key' exists and it stores a QNum.
 191  *
 192  * Return number mapped by 'key'.
 193  */
 194 double qdict_get_double(const QDict *qdict, const char *key)
 195 {
 196     return qnum_get_double(qobject_to(QNum, qdict_get(qdict, key)));
 197 }
 198
 199 /**
 200  * qdict_get_int(): Get an integer mapped by 'key'
 201  *
 202  * This function assumes that 'key' exists and it stores a
 203  * QNum representable as int.
 204  *
 205  * Return integer mapped by 'key'.
 206  */
 207 int64_t qdict_get_int(const QDict *qdict, const char *key)
 208 {
 209     return qnum_get_int(qobject_to(QNum, qdict_get(qdict, key)));
 210 }
 211
 212 /**
 213  * qdict_get_bool(): Get a bool mapped by 'key'
 214  *
 215  * This function assumes that 'key' exists and it stores a
 216  * QBool object.
 217  *
 218  * Return bool mapped by 'key'.
 219  */
 220 bool qdict_get_bool(const QDict *qdict, const char *key)
 221 {
 222     return qbool_get_bool(qobject_to(QBool, qdict_get(qdict, key)));
 223 }
 224
 225 /**
 226  * qdict_get_qlist(): If @qdict maps @key to a QList, return it, else NULL.
 227  */
 228 QList *qdict_get_qlist(const QDict *qdict, const char *key)
 229 {
 230     return qobject_to(QList, qdict_get(qdict, key));
 231 }
 232
 233 /**
 234  * qdict_get_qdict(): If @qdict maps @key to a QDict, return it, else NULL.
 235  */
 236 QDict *qdict_get_qdict(const QDict *qdict, const char *key)
 237 {
 238     return qobject_to(QDict, qdict_get(qdict, key));
 239 }
 240
 241 /**
 242  * qdict_get_str(): Get a pointer to the stored string mapped
 243  * by 'key'
 244  *
 245  * This function assumes that 'key' exists and it stores a
 246  * QString object.
 247  *
 248  * Return pointer to the string mapped by 'key'.
 249  */
 250 const char *qdict_get_str(const QDict *qdict, const char *key)
 251 {
 252     return qstring_get_str(qobject_to(QString, qdict_get(qdict, key)));
 253 }
 254
 255 /**
 256  * qdict_get_try_int(): Try to get integer mapped by 'key'
 257  *
 258  * Return integer mapped by 'key', if it is not present in the
 259  * dictionary or if the stored object is not a QNum representing an
 260  * integer, 'def_value' will be returned.
 261  */
 262 int64_t qdict_get_try_int(const QDict *qdict, const char *key,
 263                           int64_t def_value)
 264 {
 265     QNum *qnum = qobject_to(QNum, qdict_get(qdict, key));
 266     int64_t val;
 267
 268     if (!qnum || !qnum_get_try_int(qnum, &val)) {
 269         return def_value;
 270     }
 271
 272     return val;
 273 }
 274
 275 /**
 276  * qdict_get_try_bool(): Try to get a bool mapped by 'key'
 277  *
 278  * Return bool mapped by 'key', if it is not present in the
 279  * dictionary or if the stored object is not of QBool type
 280  * 'def_value' will be returned.
 281  */
 282 bool qdict_get_try_bool(const QDict *qdict, const char *key, bool def_value)
 283 {
 284     QBool *qbool = qobject_to(QBool, qdict_get(qdict, key));
 285
 286     return qbool ? qbool_get_bool(qbool) : def_value;
 287 }
 288
 289 /**
 290  * qdict_get_try_str(): Try to get a pointer to the stored string
 291  * mapped by 'key'
 292  *
 293  * Return a pointer to the string mapped by 'key', if it is not present
 294  * in the dictionary or if the stored object is not of QString type
 295  * NULL will be returned.
 296  */
 297 const char *qdict_get_try_str(const QDict *qdict, const char *key)
 298 {
 299     QString *qstr = qobject_to(QString, qdict_get(qdict, key));
 300
 301     return qstr ? qstring_get_str(qstr) : NULL;
 302 }
 303
 304 static QDictEntry *qdict_next_entry(const QDict *qdict, int first_bucket)
 305 {
 306     int i;
 307
 308     for (i = first_bucket; i < QDICT_BUCKET_MAX; i++) {
 309         if (!QLIST_EMPTY(&qdict->table[i])) {
 310             return QLIST_FIRST(&qdict->table[i]);
 311         }
 312     }
 313
 314     return NULL;
 315 }
 316
 317 /**
 318  * qdict_first(): Return first qdict entry for iteration.
 319  */
 320 const QDictEntry *qdict_first(const QDict *qdict)
 321 {
 322     return qdict_next_entry(qdict, 0);
 323 }
 324
 325 /**
 326  * qdict_next(): Return next qdict entry in an iteration.
 327  */
 328 const QDictEntry *qdict_next(const QDict *qdict, const QDictEntry *entry)
 329 {
 330     QDictEntry *ret;
 331
 332     ret = QLIST_NEXT(entry, next);
 333     if (!ret) {
 334         unsigned int bucket = tdb_hash(entry->key) % QDICT_BUCKET_MAX;
 335         ret = qdict_next_entry(qdict, bucket + 1);
 336     }
 337
 338     return ret;
 339 }
 340
 341 /**
 342  * qdict_clone_shallow(): Clones a given QDict. Its entries are not copied, but
 343  * another reference is added.
 344  */
 345 QDict *qdict_clone_shallow(const QDict *src)
 346 {
 347     QDict *dest;
 348     QDictEntry *entry;
 349     int i;
 350
 351     dest = qdict_new();
 352
 353     for (i = 0; i < QDICT_BUCKET_MAX; i++) {
 354         QLIST_FOREACH(entry, &src->table[i], next) {
 355             qdict_put_obj(dest, entry->key, qobject_ref(entry->value));
 356         }
 357     }
 358
 359     return dest;
 360 }
 361
 362 /**
 363  * qentry_destroy(): Free all the memory allocated by a QDictEntry
 364  */
 365 static void qentry_destroy(QDictEntry *e)
 366 {
 367     assert(e != NULL);
 368     assert(e->key != NULL);
 369     assert(e->value != NULL);
 370
 371     qobject_unref(e->value);
 372     g_free(e->key);
 373     g_free(e);
 374 }
 375
 376 /**
 377  * qdict_del(): Delete a 'key:value' pair from the dictionary
 378  *
 379  * This will destroy all data allocated by this entry.
 380  */
 381 void qdict_del(QDict *qdict, const char *key)
 382 {
 383     QDictEntry *entry;
 384
 385     entry = qdict_find(qdict, key, tdb_hash(key) % QDICT_BUCKET_MAX);
 386     if (entry) {
 387         QLIST_REMOVE(entry, next);
 388         qentry_destroy(entry);
 389         qdict->size--;
 390     }
 391 }
 392
 393 /**
 394  * qdict_is_equal(): Test whether the two QDicts are equal
 395  *
 396  * Here, equality means whether they contain the same keys and whether
 397  * the respective values are in turn equal (i.e. invoking
 398  * qobject_is_equal() on them yields true).
 399  */
 400 bool qdict_is_equal(const QObject *x, const QObject *y)
 401 {
 402     const QDict *dict_x = qobject_to(QDict, x);
 403     const QDict *dict_y = qobject_to(QDict, y);
 404     const QDictEntry *e;
 405
 406     if (qdict_size(dict_x) != qdict_size(dict_y)) {
 407         return false;
 408     }
 409
 410     for (e = qdict_first(dict_x); e; e = qdict_next(dict_x, e)) {
 411         const QObject *obj_x = qdict_entry_value(e);
 412         const QObject *obj_y = qdict_get(dict_y, qdict_entry_key(e));
 413
 414         if (!qobject_is_equal(obj_x, obj_y)) {
 415             return false;
 416         }
 417     }
 418
 419     return true;
 420 }
 421
 422 /**
 423  * qdict_destroy_obj(): Free all the memory allocated by a QDict
 424  */
 425 void qdict_destroy_obj(QObject *obj)
 426 {
 427     int i;
 428     QDict *qdict;
 429
 430     assert(obj != NULL);
 431     qdict = qobject_to(QDict, obj);
 432
 433     for (i = 0; i < QDICT_BUCKET_MAX; i++) {
 434         QDictEntry *entry = QLIST_FIRST(&qdict->table[i]);
 435         while (entry) {
 436             QDictEntry *tmp = QLIST_NEXT(entry, next);
 437             QLIST_REMOVE(entry, next);
 438             qentry_destroy(entry);
 439             entry = tmp;
 440         }
 441     }
 442
 443     g_free(qdict);
 444 }